coolant issue--need help

A new cap may be in order. Old ones get weak and tend to blow off before they should. My 328 did that occasionally but a new radiator cap - a standard 15 PSI Stant, available at any auto parts store - eliminated it. If it continues with a new cap, there could be issues involved that we don't need to talk about now. Try a new cap and see if that solves the problem.

It is normal for coolant to come "bubbling out" if you remove a cap on a hot engine.

 

I had the same issue, at one point my car started purging a bit of coolant every time I drove it. It went on for a couple months before I put a new cap on it. Problem gone. My old cap just lost the proper spring tension. Try that first.

 

Definately get a new cap but as noted 10 minutes is not enough time IMO to safely remove the expansion tank cap...the engine/coolant is still hot.

 

+3

Get a new cap, I am on my 3rd in 11 years & make sure its a 1.1 bar cap at that.

I carry a spare in the toolkit because once it starts tossing out coolant its a short walk to overheated heads etc.

 

+4 on the new cap. They are not expensive, so just do it. But if, in your exuberance to get the car ready for the spring, you "topped up" the coolant and didn't leave enough room in the expansion tank, the system could just be spitting out some of the excess. I used to have that problem with old Jaguars. You change the fluid and then drive the car for a while, stop and watch the puddle of coolant grow under the car. After two or three rides, the system found its level and that was that, no more spitting. I seem to remember the 308 doing that also after I did the engine-out service and refilled the system with fresh fluid.

 

Thats a good point - the "full" level in the exp tank (when engine is cold) is a bit low in comparison to what you might expect. I don't recall the specified level but it's not unusual for them to spit a bit after draining/refilling the coolant because it's easy to add a bit too much coolant.

FWIW, I think everybody pretty much uses a standard 15PSI rad cap but the specs on the 328 actually call for 12.8 PSI if I remember right. Seems to me if you really used a 13psi cap (is there such a thing?) it would tend to spit quite regularly. Fortunately, the radiator seams have proven able to handle 15PSI!

 

There was a spec in the owners manual. I think on my car is was 10cm. 6 inches. I think when cold I'm 1/3 full in the expansion tank. The measurement is just what comes to mind, I could be completely off.

 

The expansion tank should be roughly half full with the rest air volume.

You can overfill it without harm if you then air bleed the front radiator.
328s have a Tstat bleeder as well.

Once complete with system belled let it all cool donw and recheck it 'at rest', you need/want about 3" -4" of air, down from the neck of the cap.

I'm calling all this from memory and a decade of ownership I'm sure The Books give an absolute dimension in Italian somewhere......

 

PV Dirk has a Mondial with a different tank/volume........the point is the same, don't jam it full with coolant....

 

What year do you have?

Fill out your profile...

Do you have "The Books"?

 

Thats the best "every day advice". I believe the owners manual specifies 6 cm from the top of the tank to level of coolant. I leave the tank a little more than half full. If the car has been sitting for some time, maybe some air as leaked into the system. Best to have the car at a slight incline with the front higher than the rear. While the engine is running, bleed the radiator first then can do the thermostat housing. when cool check/adjust the level of the tank. I change the coolant in my 328 every year and it takes about 3 times for me to get all the air out of the system. But when done and the proper level in the tank, I've had no problems with any coolant burping out of the system. I do have a new cap from a couple of years ago when I overhauled the coolant system. Good luck and keep driving.

 

Stick your index finger into the reservoir. Your fingertip should be in the coolant..

This is, obviously, an engine-cold test.

 

LOL! Yea.....6 cm sounds right for a 308/328 tank...when cold.